WebUSB bindings part 3

Source/modules/webusb/USBInterface.idl

Index: Source/modules/webusb/USBInterface.idl
diff --git a/Source/modules/webusb/USBInterface.idl b/Source/modules/webusb/USBInterface.idl
new file mode 100644
index 0000000000000000000000000000000000000000..c4b37b685613254ea3a779f59d20daae967c4684
--- /dev/null
+++ b/Source/modules/webusb/USBInterface.idl
@@ -0,0 +1,15 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// http://reillyeon.github.io/webusb/#interfaces
+
+[
+    Constructor(USBConfiguration configuration, octet interfaceNumber),
+    RaisesException=Constructor,
+    GarbageCollected,
+    RuntimeEnabled=WebUSB,
+] interface USBInterface {
+    readonly attribute octet interfaceNumber;
+    // readonly attribute sequence<USBAlternateInterface> alternates;
+};